PEGME-bonded SnO2 quantum dots for excellent photocatalytic activity

Abstract

The ultrafine SnO2 quantum dots (QDs) modified with poly(ethylene glycol methyl ether) (PEGME) (PEGME–SnO2 QDs) were synthesized via hydrothermal method. X-ray diffraction and high-resolution transmission electron microscopy were employed to illustrate that the PEGME–SnO2 QDs are uniform, monodispersed and about 4 nm in diameter. Then infrared spectrum and thermogravimetric analysis were used to prove that PEGME groups are bound tightly to SnO2 surfaces. The as-synthesized PEGME–SnO2 QDs excellently achieved photocatalytic degradation to Rhodamine B dye (RhB). The photon efficiency of the PEGME–SnO2 QDs catalyst and corresponding RhB dye degradation rate constant could reach 0.0058% and 9.98 × 10−2 min−1, respectively. This outstanding photocatalytic performance could be attributed to not only large surface-to-volume ratio and high crystallinity of the ultrafine and monodispersed QDs, but also good hydrophilicity and conductivity of the PEGME surface modifier. Remarkably, such PEGME–SnO2 QDs with outstanding photocatalytic efficiency and stable recyclability are promising to be applied to environmental purification.